Estimation of time to compromised tenability in fires: is it time to change paradigms?

The ISO standard 13571 estimates the time to the compromised tenability of people in enclosed fires. This is understood as the time which must be available for the structural design to pass an evacuation, or an escape paradigm for the evacuation of burning buildings. As with all emergency response planning values, such once-in-a-lifetime events cannot readily be validated side-by-side. Consequently, risk assessors must refer to animal-based reference data fitting the scenario of concern closely. The analysis detailed in this paper used the concentration × time (Cxt)-matrix of point of departures (PODs) from rats acutely exposed to carbon monoxide (CO), which is amongst the most abundant toxic fire gases. The objective of the analysis was to clarify whether the time- and effect-adjusted nonlethal threshold concentration LCt01 × 1/3 from acute rat inhalation studies is suited to model thresholds characterizing any 'impairment of escape' in humans. Modeled outcomes are compared with published reference data from human volunteers exposed at the similar C × t's of CO at 800 ppm × 1-h and 100 ppm × 8-h. These exposure durations match the maximum escape duration of 1-h considered in the ISO standard 13571 and standards enforcing occupational exposure limits of 8-h duration. The reference PODs indicative of 'impairment of escape' in healthy adults relied on C × t's below those eliciting any loss of motor function or psychoneurological functions. The comparison of the LCt01 × 1/3 based modeled outcomes from rats match favorably with the effect-based PODs from humans. Consistent with published evidence from humans, carboxyhemoglobin (COHb) saturation-a biomarker of exposure rather than of effect-failed to reliably predict effect-based outcomes. Unlike the LCt01 × 1/3 threshold approach, the COHb-based median approach used by ISO TS 13571 is inconsistent with human evidence and both over- and under-estimates the CO-related potency for causing incapacitation at non-toxic and critically-toxic C × 's, respectively. In summary, it seems timely that the ISO TS 13571 standard pays attention to scientific progress in relevant toxicity information and refinements to scientific methods shown to adequately predict human risks.

Multivariate Statistical Analysis of Cigarette Design Feature Influence on ISO TNCO Yields.

The aim of this study is to explore how differences in cigarette physical design parameters influence tar, nicotine, and carbon monoxide (TNCO) yields in mainstream smoke (MSS) using the International Organization of Standardization (ISO) smoking regimen. Standardized smoking methods were used to evaluate 50 U.S. domestic brand cigarettes and a reference cigarette representing a range of TNCO yields in MSS collected from linear smoking machines using a nonintense smoking regimen. Multivariate statistical methods were used to form clusters of cigarettes based on their ISO TNCO yields and then to explore the relationship between the ISO generated TNCO yields and the nine cigarette physical design parameters between and within each cluster simultaneously. The ISO generated TNCO yields in MSS are 1.1-17.0 mg tar/cigarette, 0.1-2.2 mg nicotine/cigarette, and 1.6-17.3 mg CO/cigarette. Cluster analysis divided the 51 cigarettes into five discrete clusters based on their ISO TNCO yields. No one physical parameter dominated across all clusters. Predicting ISO machine generated TNCO yields based on these nine physical design parameters is complex due to the correlation among and between the nine physical design parameters and TNCO yields. From these analyses, it is estimated that approximately 20% of the variability in the ISO generated TNCO yields comes from other parameters (e.g., filter material, filter type, inclusion of expanded or reconstituted tobacco, and tobacco blend composition, along with differences in tobacco leaf origin and stalk positions and added ingredients). A future article will examine the influence of these physical design parameters on TNCO yields under a Canadian Intense (CI) smoking regimen. Together, these papers will provide a more robust picture of the design features that contribute to TNCO exposure across the range of real world smoking patterns.

Spatial and temporal variation of particulate matter and gaseous pollutants in 26 cities in China.

O3 and PM2.5 were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China's urban air quality will be evaluated using six factors (SO2, NO2, O3, CO, PM2.5 and PM10) from the beginning of 2013. To achieve the new air quality standard, it is extremely important to have a primary understanding of the current pollution status in various cities. The spatial and temporal variations of the air pollutants were investigated in 26 pilot cities in China from August 2011 to February 2012, just before the new standard was executed. Hourly averaged SO2, NO2 and PM10 were observed in 26 cities, and the pollutants O3, CO and PM2.5 were measured in 15 of the 26 cities. The concentrations of SO2 and CO were much higher in the cities in north China than those in the south. As for O3 and NO2, however, there was no significant difference between northern and southern cities. Fine particles were found to account for a large proportion of airborne particles, with the ratio of PM2.5 to PM10 ranging from 55% to 77%. The concentrations of PM2.5 (57.5 microg/m3) and PM10 (91.2 microg/m3) were much higher than the values (PM2.5: 11.2 microg/m3; PM10: 35.6 microg/m3) recommended by the World Health Organization. The attainment of the new urban air quality standard in the investigated cities is decreased by 20% in comparison with the older standard without considering O3, CO and PM2.5, suggesting a great challenge in urban air quality improvement, and more efforts will to be taken to control air pollution in China.

Carbon monoxide from neighbouring restaurants: the need for an integrated multi-agency response.

BACKGROUND: Carbon monoxide (CO) is a colourless, odourless toxic gas produced during incomplete combustion of carbon-based fuels. Most CO incidents reported to the UK Health Protection Agency (HPA) are due to faulty gas appliances, and legislation exists to ensure gas appliances are properly installed. METHODS: We present three CO poisoning incidents of unusual origin reported to the HPA. In each, residents living above restaurants were poisoned after workers left charcoal smouldering overnight in specialist or traditional ovens whilst ventilation systems were turned off. This led to production of CO, which travelled through floorboards and built up to dangerous concentrations in the flats. RESULTS: Working with local authorities, these incidents were investigated and resolved, and work was conducted to prevent further occurrences. CONCLUSIONS: The novel nature of these CO incidents led to delays in recognition and subsequent remedial action. Although previously undescribed, it is likely that due to the number of residences built above restaurants and the rising popularity of traditional cooking methods, similar incidents may be occurring and could increase in frequency. Multi-agency response and reporting mechanisms could be strengthened. Awareness raising in professional groups and the public on the importance of correct ventilation of such appliances is vital.

Development of emission factors and emission inventories for motorcycles and light duty vehicles in the urban region in Vietnam.

This paper reports on a 2-year emissions monitoring program launched by the Centre for Environmental Monitoring of the Vietnam Environment Administration which aimed at determining emission factors and emission inventories for two typical types of vehicle in Hanoi, Vietnam. The program involves four major activities. A database for motorcycles and light duty vehicles (LDV) in Hanoi was first compiled through a questionnaire survey. Then, two typical driving cycles were developed for the first time for motorcycles and LDVs in Hanoi. Based on this database and the developed driving cycles for Hanoi, a sample of 12 representative test vehicles were selected to determine vehicle specific fuel consumption and emission factors (CO, HC, NOx and CO(2)). This set of emission factors were developed for the first time in Hanoi with due considerations of local driving characteristics. In particular, it was found that the emission factors derived from Economic Commission for Europe (ECE) driving cycles and adopted in some previous studies were generally overestimated. Eventually, emission inventories for motorcycles and LDVs were derived by combining the vehicle population data, the developed vehicle specific emission factors and vehicle kilometre travelled (VKT) information from the survey. The inventory suggested that motorcycles contributed most to CO, HC and NOx emissions while LDVs appeared to be more fuel consuming.

PM2.5 and CO concentrations inside an indoor go-kart facility.

Three acute cardiovascular events within a 4-month period among drivers at an indoor go-kart arena prompted a visit to assess the magnitude of potentially hazardous air pollutant levels within the facility and help identify control measures. Carbon monoxide (CO) and particulate matter with aerodynamic diameters < 2.5 microm (PM2.5) were measured with personal, continuous-reading instruments to capture their spatial and temporal variability. Average driver and track CO levels during the sampling visit were comparable to state standards for worker exposures and exceeded some health-based guidelines. Average PM2.5 levels were low compared with regulatory standards, but transient PM2.5 peaks of unknown health impact were observed. Driver exposures were modestly but significantly higher than track concentrations measured by stationary monitors and substantially higher than outdoor concentrations. Driver exposures were partitioned into three components, attributed to (1) outdoor pollutants that were drawn unfiltered into the facility, (2) the persistent track cloud from previous races, and (3) proximity to the exhausts of other go-karts while driving in a race. Track cloud and tailpipe proximity components were the dominant contributors to driver CO exposure. The track cloud component lagged the number of go-karts on the track by 10-15 min. The dominant contributor to driver PM2.5 exposure was either the track cloud or outdoor component, depending on how many go-karts were racing simultaneously on the track. Transient spikes in PM2.5 were caused by proximity to other karts' tailpipes during passing events. Recommended methods for decreasing the track cloud component include modifying the ventilation system, race schedules, and number of go-karts racing simultaneously. The tailpipe proximity component can be reduced only by modifying go-kart exhausts or engines. This work represents a brief, limited sampling visit to a single facility, but it demonstrates the levels that are possible on a fairly high-usage afternoon. Future studies should be conducted to assess representative go-kart facility exposures at multiple facilities on multiple days.

Air pollution forecasting in Ankara, Turkey using air pollution index and its relation to assimilative capacity of the atmosphere.

Spatial and temporal variations in concentrations of CO, NO, NO(2), SO(2), and PM(10), measured between 1999 and 2000, at traffic-impacted and residential stations in Ankara were investigated. Air quality in residential areas was found to be influenced by traffic activities in the city. Pollutant ratios were proven to be reliable tracers to differentiate between different sources. Air pollution index (API) of the whole city was calculated to evaluate the level of air quality in Ankara. Multiple linear regression model was developed for forecasting API in Ankara. The correlation coefficients were found to be 0.79 and 0.63 for different time periods. The assimilative capacity of Ankara atmosphere was calculated in terms of ventilation coefficient (VC). The relation between API and VC was investigated and found that the air quality in Ankara was determined by meteorology rather than emissions.

Air quality management in Mexico.

Several significant program and policy measures have been implemented in Mexico over the past 15 yr to improve air quality. This article provides an overview of air quality management strategies in Mexico, including (1) policy initiatives such as vehicle use restrictions, air quality standards, vehicle emissions, and fuel quality standards, and (2) supporting programs including establishment of a national emission inventory, an air pollution episodes program, and the implementation of exposure and health effects studies. Trends in air pollution episodes and ambient air pollutant concentrations are described.

Household CO and PM measured as part of a review of China's National Improved Stove Program.

UNLABELLED: In 2001-2003, a team of researchers from the United States and China performed an independent, multidisciplinary review of China's National Improved Stove Program carried out since the 1980s. As part of a 3500-household survey, a subsample of 396 rural households were monitored for particulate matter less than 4 microm (PM(4)) in kitchens and living rooms over 24 h, of which 159 were measured in both summer and winter. Carbon monoxide was measured in a 40% subsample. The results of this indoor air quality (IAQ) component indicate that for nearly all household stove or fuel groupings, PM(4) levels were higher than - and sometimes more than twice as high as - the national PM(10) standard for indoor air (150 microg PM(10)/m(3)). If these results are typical, then a large fraction of China's rural population is now chronically exposed to levels of pollution far higher than those determined by the Chinese government to harm human health. Further, we observed highly diverse fuel usage patterns in these regions in China, supporting the observations in the household survey of multiple stoves being present in many kitchens. Improved stoves resulted in reduced PM(4) from biomass fuel combinations, but still not at levels that meet standards, and little improvement was observed in indoor pollution levels when other unimproved stoves were present in the same kitchen. As many households change fuels according to daily and seasonal factors, resulting in different seasonal concentrations in living rooms and kitchens, assessing health implications from fuel use requires longitudinal evaluation of fuel use and IAQ levels, combined with accurate time-activity information. PRACTICAL IMPLICATIONS: Leaving aside the difficult issue of enforcement, it is uncertain whether Chinese household IAQ standards represent realistic objectives for current attainment given current patterns of energy consumption in rural China, which rely so heavily on unprocessed solid fuels. Even when used with chimneys, these fuels emit substantial pollution into the household environment. It is probable that low-emission technologies involving gaseous/liquid fuels or high combustion - efficiency biomass stoves need to be promoted in order to achieve these standards for the greater part of the population.

Statistical modelling of CO and NO2 concentrations in the Athens area. Evaluation of emission abatement policies.

GOAL, SCOPE AND BACKGROUND: This paper describes a statistical modelling approach, suggested as a policy tool in the Athens area for the assessment of the emissions reduction level required to meet the air quality standards for two criteria air pollutants. METHODS: More than ten years of hourly CO and NOx-NO2 concentration data measured by the monitoring network of the Hellenic Ministry for the Environment, Physical Planning and Public Works were analyzed and the original dataset has been reduced using a data evaluation procedure. RESULTS AND DISCUSSION: Seasonal pollutant concentration trends suggested that the reduction of CO and NOx concentrations observed in the beginning of the '90s is almost entirely attributed to the increase of the catalyst-equipped cars during this period. The numerical parameters of an empirical model relating EU standard exceedances with mean annual concentrations were defined and the model was validated using datasets from years that were not used for the estimation of these parameters. This model was used in conjunction with a roll-back equation as a policy tool for the assessment of the effect of different CO and NOx emissions reduction scenarios on air quality standard compliance for CO and NO2. Results predicted with this empirical modelling approach were assessed with monitored data averaged over a 3-year period, giving satisfactory results. CONCLUSION: A methodology suggested for assessing the effects of different emissions reduction scenarios on air quality standard attainment was successfully applied for CO and NO2 in the Athens area. RECOMMENDATION AND PERSPECTIVE: The proposed methodology can provide a useful tool for the evaluation of policies already in progress as well as the development of future policies for emissions reduction in urban areas with similar characteristics, aiming at air quality standard compliance on a timely manner, Such a methodology could be applied in other urban areas of Greece characterized by dense traffic, therefore assisting the development of national policies in relation to air pollutants for which standard exceedances occur.

Development of an aggregate Air Quality Index for an urban Mediterranean agglomeration: relation to potential health effects.

It is very useful for the authorities and the people to have daily easy understandable information about the levels of air pollution and the proper measures to be taken for the protection of human health. In this paper we develop an aggregate Air Quality Index (AQI) based on the combined effects of five criteria pollutants (CO, SO2, NO2, O3 and PM10) taking into account the European standards. We evaluate it for each monitoring station and for the whole area of Athens, Greece, an area with serious air pollution problems. A comparison was made with a modified version of Environmental Protection Agency/USA (USEPA) maximum value AQI model adjusted for European conditions. Hourly data of air pollutants from 4 monitoring stations, available during 1983-1999, were analysed for the development of the proposed index. The analysis reveals the Athenian population exposure reaches high levels and during last years a gradual increase of days with unhealthy conditions was detected. The proposed aggregate model estimates more effectively the exposure of citizens comparing with the modified USEPA maximum value model, because counts the impact of all the pollutants measured. Towards the informing and protection of the citizens in an urban agglomeration this model advantages as a political and administrative tool for the design of abatement strategies and effective measures of intervention.

An evaluation of conditions that may affect the performance of houseboat exhaust stacks in prevention of carbon monoxide poisonings from generators.

National Institute for Occupational Safety and Health (NIOSH) researchers evaluated two exhaust stack designs for reducing carbon monoxide (CO) exposures from gasoline-powered generator exhaust on houseboats. Tests were conducted (a) after dark, (b) in high-temperature and high-humidity environments, (c) during temperature inversions, (d) under various generator loads, and (e) at different houseboat trim angles. Two different designs of houseboat exhaust stacks were evaluated and compared with the side-exhaust configuration, which is standard on many houseboats. The two designs were flagpole and vertical stack. Both exhaust stacks performed dramatically better than the standard water level, side-exhaust configuration. The highest mean CO concentrations on the upper and lower decks of the houseboat with the vertical exhaust stack were 27 ppm and 17 ppm. The highest mean CO concentrations on the upper and lower decks of the houseboat with the modified flagpole stack were 5 ppm and 2 ppm. These findings are much lower than the 67 ppm and 341 ppm for the highest mean CO concentrations found on the upper and lower decks of houseboats having the usual side-exhausted configuration. The NIOSH evaluation also indicated that high-temperature and high-humidity levels, temperature inversions, generator loading, and houseboat trim angles had little effect on the exhaust stack performance. It also demonstrated the importance of proper design and installation of exhaust stacks to ensure that all exhaust gases are released through the stack. Based on the results of this work, NIOSH investigators continue to recommend that houseboat manufacturers, rental companies, and owners retrofit their gasoline-powered generators with exhaust stacks to reduce the hazard of CO poisoning and death to individuals on or near the houseboat.

An analysis of effects of San Diego wildfire on ambient air quality.

The impact of major gaseous and particulate pollutants emitted by the wildfire of October 2003 on ambient air quality and health of San Diego residents before, during, and after the fire are analyzed using data available from the San Diego County Air Pollution Control District and California Air Resources Board. It was found that fine particulate matter (PM) levels exceeded the federal daily 24-hr average standard during the fire. There was a slight increase in some of the gaseous pollutants, such as carbon monoxide, which exceeded federal standards. Ozone (O3) precursors, such as total hydrocarbons and methane gases, experienced elevated concentration during the fire. Fortunately, the absence of sunlight because of the cloud of thick smoke that covered most of the county during the fire appears to have prevented the photochemical conversion of the precursor gases to harmful concentrations of O3. Statistical analysis of the compiled medical surveillance data has been used to establish correlations between pollutant levels in the region and the resultant health problems experienced by the county citizens. The study shows that the increased PM concentration above the federal standard resulted in a significant increase in hospital emergency room visits for asthma, respiratory problems, eye irritation, and smoke inhalation. On the basis of the findings, it is recommended that hospitals and emergency medical facilities engage in pre-event planning that would ensure a rapid response to an impact on the healthcare system as a result of a large wildfire and appropriate agencies engage in the use of all available meteorological forecasting resources, including real-time satellite imaging assets, to accurately forecast air quality and assist firefighting efforts.

Monitoring of air pollution in the atmosphere around Oman Liquid Natural Gas (OLNG) plant.

This study was basically designed to assess the potential environmental air quality impacts arising from the existing two operational trains at the Oman Liquid Natural Gas (OLNG) plant. The results of the paper contain a baseline survey of the existing environment. The pollutants studied included methane (CH4), non-methane hydrocarbons (NMHC), carbon monoxide (CO), nitrogen oxides (NOx), and suspended particulate matters (dust PM 10). Meteorological parameters monitored simultaneously include wind speed and direction, air temperature, and relative humidity. The air quality data were used to determine the diurnal and monthly variations in the pollutants. Description levels of the pollutants with respect to meteorological data were also used in analysis. Moreover, a statistical analysis of the collected data was presented. Generally, the results indicated that the mean concentrations of pollutants were low to cause any significant impact in air quality. The area had no problem in meeting the air quality standards for CO and NO2. It was also found that there was a random relationship between CO and NMHC, and between NO and NOx (no apparent correlation). The diurnal peaks of NOx, NO2, THC, and NMHC over a 24-h period were observed at around 9:00-10:00 AM (morning peak). For NO, NO2, and NOx, another peak was seen at around 5:00 PM (evening peak). Furthermore, the measured concentrations for NO2, NOx, and CO were found higher in winter than in summer. The study would help to gain a better understanding of local background levels of air pollutants at the area prior to the construction of new industrial projects, and to prepare action plans for controlling pollution in the area.

[Use of the "exposure level-body condition" relations for evaluation of the effects of complex atmospheric pollution]. / Ispol'zovanie zavisimosti "kontsentratsiia-status organizma" dlia otsenki vozdeistviia kompleksa atmosfernykh zagriaznenii.

Criteria for the organism status arrangement in terms of environmental effects expression from adaptation to its break-down were worked up. The criteria may be used in developing of the hygienic standardization of environmental effects.